constant noise

patrickt · #4 (**permalink**) 11-23-2016, 06:36 AM

Quote:

Originally Posted by 123redtail

no top, full convertible . I have 2 rollbars . sounds like leaves blowing on the street.

OK, the easiest, and most harmless, would be air noise, maybe in combination with the backs of your seats, carpeting, etc. You don't get that though until you get up around 30mph or so. When I do a "noise diagnosis" on my Cobra, I get it up to about 45mph, on a smooth road, then put it in neutral and kill the engine. The only thing I hear is the air noise which, on my car, sounds like just like a good leak in a tire. I can still remember the first time I did that I thought, for an instant, "oh my gosh my fire extinguisher must be leaking."

But, the sound of leaves, is just plain different. And, of course, if you can hear the sound at very low speeds, then it can't be air noise at all.

So, take it up to about 45mph, on a smooth road, kill the engine, and then listen as carefully as you can, then, ever so lightly, put your foot on the brakes and see if you can change the sound as you increase the pressure. If you can't, then that pretty much eliminates the brake pads and rotors. Then, pump your tires up to 40psi and repeat the test to see if the sound has changed (then put your tires back down to regular pressure). That will point you to tires. If you still haven't found the sound, then you're going to have to jack the car up and look for (if you are really lucky) something, like a plastic bag, stuck under your car and hitting the drive shaft, inner wheel, etc. Then use a mechanic's stethoscope to listen to all the moving parts as one of your kids spins the rear wheels by hand, as fast as he can, with the car in neutral. Put the stethoscope on everything from the transmission, to the rear differential, to the hub area of the bearings. Then have him spin the front wheels while you do the same thing. There's only so many things that it can be, and you will eventually find it (especially if you discover that one wheel sounds significantly different than its mate on the other side of the car).